TikTok did not specifically take over any particular app, but it gained immense popularity and disrupted the dominance of existing social media platforms, particularly Vine and Musical.ly.

1. Vine: TikTok's rise to prominence can be traced back to its similarities with Vine, a short-form video app that was popular in the early 2010s. Vine allowed users to create and share 6-second looping videos, which became a cultural phenomenon. However, Vine was shut down in 2017 due to various reasons, including competition from other platforms and internal management issues. TikTok filled the void left by Vine, offering a similar concept of short videos but with enhanced features and a larger user base.

2. Musical.ly: TikTok's foundation can be directly linked to the acquisition of Musical.ly, a lip-syncing app that gained significant traction among teenagers and young adults. In 2018, TikTok's parent company, ByteDance, acquired Musical.ly and merged it with TikTok, rebranding the app as TikTok. This move allowed TikTok to inherit Musical.ly's user base and features, including the ability to create lip-sync videos and add music to clips. The integration of Musical.ly's community into TikTok played a crucial role in its rapid growth and popularity.

TikTok's success can be attributed to several factors:

1. User-Friendly Interface: TikTok offers a simple and intuitive interface that allows users to easily create and edit videos. It provides a wide range of creative tools, filters, effects, and music options, enabling users to produce engaging content without extensive technical skills.

2. Algorithmic Recommendation System: TikTok's algorithm analyzes user preferences, interactions, and viewing habits to curate a personalized "For You" feed. This algorithmic recommendation system ensures that users are exposed to content tailored to their interests, increasing engagement and user retention.

3. Viral Challenges and Trends: TikTok is known for its viral challenges and trends, where users participate in various creative and entertaining activities. These challenges often involve users replicating specific dance routines, lip-syncing to popular songs, or engaging in comedic skits. Such trends create a sense of community and encourage users to actively participate and share their own versions, further fueling the app's popularity.

4. Influencer Culture: TikTok has nurtured a thriving community of influencers who have gained significant followings and influence through their creative content. These influencers collaborate with brands, create sponsored content, and engage with their followers, contributing to TikTok's growth and attracting more users to the platform.

It's important to note that while TikTok gained popularity and disrupted the social media landscape, it did not completely replace any specific app. Instead, it carved out its own niche by offering a unique combination of features and capitalizing on the growing demand for short-form video content.